Building Digital Battery System via Energy Digitization for Sustainable 5G Power Feeding

In the upcoming era of 5G, the number of base stations, edge computing nodes and data centers is believed to be three to five times more than that of 4G. Serious challenges on the deployment and operation of 5G networks and services arise, especially on how to build and maintain battery energy storage systems for sustainable 5G power feeding at low cost for all scenarios. Although battery has long been used as a major backup power in various communications systems, current battery systems essentially are "dumb devices." In the current battery systems, the charging/discharging energy flow is continuous due to the fixed series-parallel cell topology adopted by existing battery systems. The fixed topology also causes the "bucket effect" at the system level due to the fact that it is incapable of handling cell difference in a battery system, leading to a series of system-level problems in terms of power density, energy efficiency, cycle life, reliability, and safety. All these will make it very challenging for sustainable 5G power feeding, which will further affect the cost-effective deployment and operation of 5G networks and services. Thanks to the recent breakthrough of power electronics semiconductors, such as power metal-oxide- semiconductor field-effect transistor (MOSFET), silicon carbide (SiC) and gallium nitride (GaN) with their outstanding material properties, it becomes feasible to carry out digital energy processing operations at high switching speed, high voltage, and feverish temperature. By building a new digital "grid-to-chip" power train using high switching speed power semiconductors, traditional analog battery systems can be transformed into digital battery systems through energy digitization, which will significantly facilitate feasible 5G deployment and operation. In this article, we will propose and describe the basic concept of energy digitization, the design framework of the digital battery system including key components, modeling, and the performance evaluation of the digital battery system. Results of experiments and real-world applications show the effectiveness and efficiency of digital battery system, which offer a promising disruptive approach to sustainable 5G power feeding.